Ground State Hyperfine Structure of Muonic Helium Atom

The muonic helium atom (μe2He) represents the simple three-body atomic system. The interaction between magnetic moments of the muon and electron leads to the hyperfine structure (HFS) of the energy levels. The investigation of the energy spectrum of this atom is important for the check of quantum electrodynamics for three-particle bound state. The ground state hyperfine splitting was measured many years ago with sufficiently high accuracy [1, 2]: ∆ν exp = 4465.004(29) MHz. (1)